A power semiconductor device such as an IGBT chip is used as a power module mounted, for example, on a power converter for a hybrid electric car and a pure electric car. The IGBT chip has a structure where several thousands to several tens of thousands of IGBT cells are repeatedly arranged. The IGBT chip is a three-terminal device having an emitter electrode, a collector electrode, and a gate electrode, in the structure of which the emitter electrode and the gate electrode are formed in an insulated state on the same plane of the IGBT chip.
In order to reduce the variation of the propagation delay time of a control signal, the gate electrode is connected to a gate wiring made of a material having a high conductivity such as aluminum, and the gate wiring is connected to a gate of the IGBT cell, for example, through a polysilicon wiring.
The emitter electrode of the IGBT chip is generally divided into multiple regions by the gate wiring (see PTL 1). The emitter electrode divided may be connected to a conductive member with solder.
In the power module mounted, for example, on a power converter for a hybrid electric car and a pure electric car, the input current tends to be increased as systems in recent years are powered up. When solder is used to connect a semiconductor device and a conductive member, an increase in the input current increases the temperature change of the semiconductor device, resulting in the degradation of the solder connecting the semiconductor device and the conductive member. Since the degradation of the solder affects the void fraction, suppression of voids that occur during soldering is an important issue in improving the life of the solder to a temperature change.